Spiral scan antenna mechanism



June 7, 1955 l. A. GETTING ErAL SPIRAL SCAN ANTENNA MECHANISM 4 Sheets-Sheet l Filed Jan. 50, 1946 mv? @v ATTORNEY June 7, 1955 Filed Jan. 30, 1946 l, A. GETTING Erm.

SPIRAL scAN ANTENNA MECHANISM FIG.2

FIG. 3

4 Sheets-Sheet 2 INVENTOR IVAN A. GETTING ALBERT W. BELLAMY ATTORNEY `lune 7, 1955 A. GETTING :TAL

SPIRAL scAN ANTENNA MECHANISM 4 Sheets-Sheet 3 Filed Jan. 30, 1946 FIG.- 6

F IGV. 7

FIG. 9

INVENTOR IVAN A. GETTING ALBERT .W. BVELLAMY lFIGS ATTORNEY June 7, 1955 l. A. GETTING ETAL sPIRAL scAN ANTENNA MECHANISM 4 Sheets-Sheet 4 Filed Jan. 30, 1946 INVENTOR IVAN A. GETTING ALBERT W. BELLAMY AT TORNEY Patented .lime 7, 1955 ffice SPIRAL SCAN ANTENNA MECHANISM Ivan A. Getting, Belmont, Mass., and Albert W. Bellamy,

North Hoilywood, Calif., assignors, by mesne assign- .ments, to the United States of America as represented by the Secretary of the Navy Application .lanuary 30, 1946, Serial No. 644,395

17 Claims. (Cl. 250--33.63)

This invention relates to an antenna nutating scan mechanism, and more particularly to a mechanical drive for causing a wave guide, used to feed radio microwave energy to an antenna, to scan in either a spiral or conical pattern, and to maintain a beam of fixed polarization throughout the scanning cycle.

In the operation of radar mechanism of the type used for directing artillery tire against aircraft, and especially low ying aircraft such as torpedo planes, it is frequently desirable that the scan accomplished by the radar antenna be in a spiral pattern since such a pattern may be restricted to a relatively small area and will provide an accurate scan of the area encompassed by the spiral. My invention provides a mechanical assembly for causing the microwave transmission emitted from an antenna to assume either a conventional conical pattern, a spiral pattern, or other pattern, as may be found desirable.

An object of this invention is to provide an assembly for selectively providing a nutating spiral, conical, or other scan of radio microwave energy.

Another object of this invention is to provide an assembly for selectively providing a nutating spiral, conical or other scan of radio microwave energy in which the antenna feed and drive are so balanced as to bring the center of percussion of the antenna feed assembly at the point of connection of the antenna feed drive and the radially movable portion of the assembly.

Other objects and advantages of this invention as well as its construction, arrangement and operation will be apparent from the following description and claims in connection with the accompanying drawings in which:

Fig. l is a sectional view taken through a vertical center line of the assembly;

Fig. 2 is a plan view illustrating the spindle, chuck body, and jaw assembly;

Fig. 3 is a plan section through the screw holes of screws 60 and 61 of Fig. 2;

Fig. 4 is a front view of the counterweight shown in Fig. 1;.`

-, Fig. 5 is a side view of Fig. 4;

Fig. 6 is a front View of the pivot jaw;

Fig. 7 is a side view of Fig. 6;

Fig. S is a front view of the counterweight jaw;

Fig. 9 is a side view of Fig. 8;

Fig. 10 is a side View in section of the gimbal ring assembly of Fig. l; and

Fig. ll is a front view partially in section of the gimbal ring assembly of Fig. 1.

Referring to Fig. 1 there is shown a housing 20 containing a hollow spindle 2l which is pinned to the armature 22 of a suitable motor 23 and caused to rotate in earings 26 and 27 in response to rotation of the armature. An enlarged portion 2S is provided on one end of spindle 21'as a means for mounting a chuck body 49, hereinafter to be described, to spindle 21. A shaft 30, slidably mounted within hollow spindle 21, is provided with a threaded hollow collar 31 on one end thereof for cooperation with a spring 32 which normally urges the shaft towards an initial position. The opposite end of shaft 36 is fastened by means of screw threads to a draw plug 24 which is slidably mounted in the enlarged portion 2S of spindle 21 and which moves longitudinally in said portion in response to longitudinal motion of rod 30. A pair of spacing pins 33 and 33a are provided at opposite ends of shaft 30 as a means for adjusting the initial setting of the shaft within hollow spindle 21. A pivotally mounted cam lever 34a which cooperates with one end of shaft 30 to cause the rod to move longitudinally in hollow spindle 21 is actuated by a suitable cam 34 in such manner as to cause longitudinal recprocatory motion of the rod. Cam 34 is driven by means of a si ltable spur gear 3S having a shaft 36 extending therefrom and driven through conventional electric clutch and brake mechanisms 37 and 38 by a second shaft 39 which is, in turn, rotated by means of a gear train 40 connected to hollow spindle 21. Cam 34 may, therefore, rotate in synchronism with the rotary motion of spindle 21 or may remain motionless as the spindle rotates by application of electromagnetic clutch and brake 37 and 3S. A control switch 38a is provided to selectively cause clutch 37 and brake 38 to be engaged and disengaged as may be desirable. When the cam rotates, cam lever 34a assumes a lateral and periodic motion, thus causing push rod 30 and draw plug 24 to assume a reciprocatory motion in order to vary the angle of tilt of a wave guide feed as hereinafter explained.

As shown, draw plug 24 is connected to a pivot jaw 41 and a counterweight jaw 42 by means of slide blocks 43, 44, 45 and 46 which are pinned to the opposite ends of a pair of bell crank levers 47 and 43, the bell crank levers being pivotally mounted to a chuck body or flange 49 by means of a pair of pins 50 and 51. Longitudinal movement of draw plug 24 causes bell cranks 47 and 4S to pivot about pins 5t) and 51 thereby causing relative movement of pivot jaw 4l and counterweight jaw 42, the jaws being simultaneously caused to move radially inwardly or outwardly depending upon the direction of the aforementioned longitudinal movement. The antenna feed and drive have been weighted by means of a counterweight 78 so as to bring the center of percussion of the antenna feed assembly at the point of connection of members and 64 in order to minimize the strain at the center of oscillation of the wobble joint. In addition, the center of gravity of counterweight 62 presents an equal and opposite force at this point, thereby accurately and dynamically balancing the unit for all scan angles. As shown in Fig. 2, chuck body 49 is fastened to spindle 21 by means of a pair of screws 52 and 53 and is thereby caused to rotate in response to rotation of spindle 21. Chuck body 49 acts as a retainer for holding pivot jaw 41 and counterweight jaw 42 in a slidable relationship.

Figs. 2 and 3 further illustrate the manner in which the counterweight and pivot jaws are slidably mounted upon and retained by chuck body. Referring to these figures, there is shown a pair of side plates 58 and 59 which are fastened to chuck body 49 by means of a pair of suitable screws 60 and 61, the side plates being so formed as to provide an overlapping portion to slidably retain jaws 41 and 42 adjacent the chuck body. A counterweight plate 62 is fastened over the lower portion of counterweight jaw 42 as shown in Fig. l. Figs. 4 and 5 demonstrate the general configuration of counterweight 62, the counterweight comprising la U-shaped plate having the base portion partially cut away and provided with drilled holes for the placement of screws by which the counterweight is fastened to counterweight jaw 42 as shown in Fig. l.

Figs. 6, 7, 8, and 9 illustrate the configuration of pivot jaw 41 and counterweight jaw 42, respectively. Referring to Figs. 6 and 7 pivot jaw 4l comprises a curved plate having a raised portion 63 extending from one side thereof and a threaded boss 6d extending from the opposite side thereof. A tongue 65 extends downwardly from the bottom of boss 64 to slidably engage a slotted portion of counterweight jaw 42. Raised portion 63 is provided with a slot 66 to receive slide block 43 which causes the jaw to move radially in response to movement of bell crank lever 47. As shown in Figs. 8 and 9, counterweight jaw 42 comprises a pair of curved tongues 67 and 63, the tongues being spaced from each other to slidably receive tongue 65 of pivot jaw 4l. therebetween. A block 69 is fastened to the tongues in the lower portion thereof, the block being provided with a slot 7d in order to receive slide block 46 which causes radial movement of the counterweight A- jaw in response to movement of bell crank lever 48. Four threaded holes 71, 72, 73 and 74 are provided to receive screws used to fasten counterweight 62 to the lower portion of the jaw.

Further referring to Fig. l, a wave guide support 75 is operatively connected to boss 64 of pivot jaw 41 by means of a choke housing or wave guide drive 76 and a counterweight 78. Support 75 is connected to wave guide drive 76 by means of a screw thread 77, while counterweight 73 is connected to the wave guide drive at one end by a suitable bolt 79 and to boss 64 at the other end by means of a cylindrical extension 8d which is tted over a suitable bearing 81 secured to boss 64. The wave guide consists of a xed portion 83 and a movable portion S4, the movable portion 84 thereof being mounted in support 75 and connected to the xed portion 83 thereof by means or" a suitable wobble joint 35. In order to provide a universal joint for mounting support 75 in a gimbal support 54, the wave guide drive 76 is mounted in a gimbal ring 86. A cap 87;1 is mounted over gimbal ring 86 by means of 3 similar screws 87a to keep out dust and dirt. Further details of the method of mounting the wave guide support are illustrated in Figs. 10 and ll.

Figs. lO and ll are sectional views taken through gimbal ring S6. Referring to the iigures, gimbal ring 86 is mounted on gimbal support 54 by means of two suitable bearings 87 and S3 mounted on oppositely disposed studs 89 and 96 screwed into gimbal support 54. The nose of wave guide drive 76, on the other hand is fastened to gimbal ring 86 by similar bearings 9i and 92 mounted on oppositely disposed studs 92a and 93 fastened in the gimbal ring at ninety degrees from the axes of studs 89 and 90. The movable portion S4 of the wave guide is retained within support 75' by means of a pair of set screws 94 and 95 which securely maintain a flange 96 of u the wave guide within choke housing 76. Flange 96, in addition to providing a retaining means for securing section 84 of the wave guide within support 75, constitutes a portion of the wobble joint connecting the fixed and movable portions of the guide.

ln operation, it will readily be understood that wave guide section 34, mounted within support 75 will assume the same scanning motion as that imparted to the support.

As heretofore stated, support 7S is mounted in gimbal i support 54 by means of a universal joint which allows support 75 and the external wave guide contained therein to assume a nutating or spiral motion as the radial distance of the axis of boss 64.- from the axis of rotation of spindle 21 is varied by the action of cam 34 operating through shaft 3) to longitudinally move draw plug Z4 and bell cranks 47 and 4S. That is to say, at all times when cam 34 is operative the wave guide within support 7 5 is caused to assume a spiral motion, but wherever cam 34 is inoperative when clutch 37 is disengaged) the wave guide will follow a conical motion. Radio microwave radiation, which is fed into the fixed portion of the wave guide will assume a pattern in space as imparted to it by nutating spiral, or conical motion of the constantly nutating movable portion of the wave guide. While a particular cam is illustrated, it should be noted that cams of various sizes and shapes may be used in order to vary the degrees of spiral patterns since this cam gives proper coverage of space being searched. When the cam is not in motion and spindle 2 is rotating a conical pattern will be realized. It will readily be understood that wave guide 84 may be used to feed a radio microwave reflector as may be found to be desirable.

While a particular embodiment of the invention has been disclosed and described, it is to be understood that various modifications and changes may be made therein without departing from the spirit and scope thereof as set forth in the appended claims.

What is claimed is:

l. An assembly for generating a spiral scan of radio microwave radiation comprising a wave guide having fixed and movable portions operatively connected by a wobble joint, a support, a gimbal system mounted on said support, a wave guide drive secured to the inner ring of said gimbal system, means for connecting said wave guide drive to the movable portion of said wave guide, a rotatable spindle, means for rotating said spindle, a flange on one end of said spindle, a shaft slidably disposedin said spindle having a draw plug on one end thereof, means for causing longitudinal motion of said shaft in response to rotation of said spindle, and means pivotally mounted on said flange operatively connecting said draw plug and said wave guide drive for causing radial movement of said wave guide drive in response to longitudinal movement of said draw plug.

2. A mechanism for generating a spiral scan of radio microwave radiation comprising a wave guide having xed and movable portions operatively connected by a wobble joint, a support, a gimbal system mounted on said support, a wave guide drive secured to the inner ring of said gimbal system, means for operatively connecting the movable portion of said wave guide to said wave guide drive, a rotatable spindle having a chuck body on one end thereof, means for rotating said spindle, a shaft slidably mounted within said spindle having a draw plug secured thereto, a pivot jaw slidably mounted on said chuck body, means connecting said pivot jaw and said draw plug for causing radial movement of said pivot jaw in response to longitudinal movement of said draw plug, means for operatively connecting said pivot jaw to said wave guide drive, and means for causing reciprocatory motion of said shaft in response to rotation of said spindle.

3. A mechanical drive for generating a spiral scan of radio microwave radiation comprising a wave guide having xed and movable portions operatively connected by a wobble joint, a support, a gimbal system mounted on said support, a wave guide drive having one end thereof fastened to the inner ring of said gimbal system, means for operatively connecting said movable portion of said wave guide to said wave guide drive, a housing, a spindle i rotatably mounted in said housing, means for rotating said spindle, a shaft slidably mounted in said spindle, means for causing reciprocatory motion of said shaft in synchronism with rotation of said spindle, a chuck body mounted on said spindle, a bell crank lever pivotally mounted on said chuck body, means for operatively connecting said bell crank and said shaft, and means for operatively connecting said bell crank and said wave guide drive.

4. A mechanical drive for generating a spiral scan of radio microwave radiation comprising a wave guide having xed and movable portions operatively connected by a wobble joint, a support, a gimbal system mounted on said support, a wave guide drive having one end thereof fastened to the inner ring of said gimbal system, means for operatively connecting the movable portion of said wave guide to said wave guide drive, a housing, a spindle rotatably mounted in said housing, means for rotating said spindle, a shaft slidably mounted in said spindle, means for causing reciprocatory motion of said shaft in synchronism with rotation of said spindle, a draw plug fastened to said shaft, a chuck body mounted on said spindle, a bell crank lever pivotally mounted on said chuck body, means for operatively connecting said draw plug and said bell crank, and means for operatively connecting said wave guide drive and said bell crank.

5. An assembly for generating a spiral scan of radio microwave radiation comprising a wave guide having fixed and movable portions operatively connected by a wobble joint, a support, a gimbal system mounted on said support, a wave guide drive having one end thereof fastened to the inner ring of said gimbal system, means for connecting the movable portion of said wave guide and vsaid wave guide drive, a rotatable spindle, means for rotating said spindle, a chuck body fastened to one end of said spindle, a pivot jaw slidably mounted in said chuck body, a shaft slidably disposed in said spindle having a draw plug fastened thereto, means for operatively connecting said wave guide drive and said pivot jaw, means for causing longitudinal movement of said shaft in response to rotation of said spindle, and means connecting said pivot jaw and said draw plug for causing radial movement of said pivot jaw in response to longitudinal movement of said draw plug.

6. An assembly for selectively providing spiral and conical scan of radio microwave radiation comprising a wave guide having fixed and movable portions operatively connected by a wobble joint, a support, a gimbal system mounted on said support, a wave guide drive having one end thereof fastened to the inner ring of said gimbal system, means for connecting said wave guide drive to the movable portion of said wave guide, a rotatable spindle having a chuck body fastened to one end thereof, means for rotating said spindle, a shaft slidably disposed in said spindle having a draw plug fastened to one end thereof, a pivot jaw slidably mounted upon said chuck body, a bell crank lever pivotally mounted on said chuck body for operatively connecting said pivot jaw and said draw plug, means for operatively connecting said wave guide drive and said pivot jaw, a cam, an arm operatively connecting said cam and said shaft, driving means for rotating said cam in synchronism with rotation of said spindle, and clutch and brake disposed in said driving means for selectively causing said cam to rotate and be held in a xed position.

7. An assembly for providing spiral and conical scan of radiation comprising a conductor having fixed and movable portions, a support, a gimbal system mounted on said support, a conductor drive mechanism having one end fastened to the inner section of said gimbal system, means connecting said drive mechanism to said movable portion of said conductor, a rotatable spindle, means for rotating said spindle, a flange on one end of said spindle, a shaft slidably disposed in said spindle having a draw plug in one end thereof, means for causing longitudinal motion of said shaft, and means on said flange operatively connecting said draw plug and said conductor drive mechanism.

8. In apparatus for providing spiral and conical scan of radiation, the combination comprising first and second wave guide sections, said first section being fixed, the second of said sections being movably supported in end to end relationship with said first section, a universal joint system, means securing said second section to said universal joint system, and means connected to said universal joint system for imparting nutating motion to said second section through said universal joint system, whereby said second section nutates about the adjacent end of said first section. i

9. In apparatus for providing spiral and conical scan of microwave radiation the combination comprising, a conductor having fixed and movable portions in end to end relationship, said fixed and movable portions being operatively connected by a wobble joint, a support, universal joint means mounted on said support, means securing said movable portion to said universal joint means whereby said movable portion is `capable of assuminga nutating motion about said fixed portion, and 'means including drive means operatively coupled to -said universal joint means for nutating said movable section about said fixed section.

10. In apparatus for providing spiral and conical scan of microwave radiation, the combination comprising, a conductor having xed and movable portions in end to end relationship, said fixed and movable portions being operatively connected by a wobble joint, a support, a gimbal system mounted on said support, means securing said movable portion to said gimbal system whereby said movable portion is capable of nutating motion about said fixed portion, means connected to said gimbal system for imparting nutating motion to said fixed portion, and

drive means connected to said last-mentioned means.

1l. An assembly for providing spiral and conical scan of radiation comprising, a hollow shaft, drive means for rotating said shaft, a wobble joint having a fixed portion and a movable portion, first wave guide means secured to said fixed portion, second wave guide means secured to said second portion, means including a universal joint connecting said shaft to said movable portion of the wobble joint, said connecting means acting to convert the rotating motion imparted to it by said shaft to a nutating motion, said mutating motion being applied by said universal joint means to said second wave guide means.

l2. An assembly as described in claim 11 wherein said connecting means includes means for selectively varying the angle of tilt of said second wave guide means.

13. An assembly as described in claim 12 further including cam operated means for controlling operation of said means for varying the tilt of said second wave guide means, whereby said second wave guide means may be spirally nutated.

14. A mechanism comprising in combination, a hollow rotatable spindle, means for driving said spindle, a ange on one end of said spindle, a shaft slidably disposed on said spindle having a draw plug in one end thereof, a pivot jaw, lever means pivotally mounted on said flange slidably connecting said draw plug and said pivot jaw and adapted to cause radial movement of said pivot jaw in response to longitudinal movement of said draw plug.

15. Apparatus as in claim 14 further including a gimbal support, a gimbal system comprising first and second annular elements, said gimbal system being pivotally Secured to said support by said first annular element, means rotatably securing said second annular element to said pivot jaw, a wave guide support secured to said second annular element, and a wave guide secured by said wave guide support in axial alignment with said second annular ele` ment, whereby said wave guide is caused to assume a rotating and nutating motion which is a function of the speed at which the spindle is driven and the radial position of said pivot jaw.

16. The combination comprising a hollow rotatable spindle having an enlarged portion at one end thereof, means for driving said spindle, a push rod slidably mounted Within said spindle, a draw plug fastened at one end of said push rod and slidably mounted in the enlarged end or' said spindle, flange means fixedly secured to said spindle at said enlarged end, a pivot jaw, bell crank lever means pivotally mounted on said flange means, the ends of said bell crank lever means being connected by slide blocks to said draw plug and said pivot jaw, and means for moving said push rod longitudinally whereby said pivot jaw is radially displaced by said bell crank lever means, a wave guide section, and means for imparting nutatory motion to said wave guide section operatively coupling said pivot jaw to said wave guide section, whereby said Wave guide section assumes a nutatory motion in synchronism with rotation of said spindle.

17. An assembly for providing spiral and conical scan of radiation comprising, a hollow shaft, means for rotating said shaft at a predetermined rate, a chuck body mounted on one end of said shaft and rotatable therewith, a pivot jaw slidably mounted on said chuck body and rotatable therewith, means slidably mounted Within said hollow shaft and connected to said pivot jaw for causing radial movement of said pivot jaw, a Wave guide section, a universal joint system having a movable portion thereof secured to said wave guide section, and means connecting said universal joint system to said pivot jaw, whereby said universal joint system imparts rotatging and nutating motion to said wave guide section, the 'rotating motion of said wave guide section being a /function of the rotating motion of said hollow shaft,

said nutating motion of said Wave guide section being a function of the radial displacement of said pivot jaw.

References Cited in the le of this patent UNTED STATES PATENTS 1,598,433 Fuog Aug. 31, 1926 2,332,383 Rost Oct. 19, 1943 2,407,305 Langstroth et al. Sept. 10, 1946 1Q 2,407,310 Lundy et a1. f Sept. 10, 1946 2,410,827 Langstroth et a1. Nov. 12, 1946 2,412,867 Briggs et al. Dec. 17, 1946 2,420,007 Older] lVIay 6, 1947 

